计算(x的平方 y的平方)dS上半球面z=根号下4-x的平方-y的平方-搜答案-拍题作业网

初二数学题：计算（y-x)×xy/x的平方-y的平方的结果是（-(xy)/(x+y)）.(y-x)xy/(x+y)(x-y)=-(xy)/(x+y)很高兴为您解答,skyhunter002为您答疑解惑

25x²-16y²=(5x+4y)(5x-4y)

原式=(x^3y^2-x^2y-x^2y+3x^3y^2)÷3x^2y=(4x^3y^2-2x^2y)÷3x^2y=4/3xy-2/3

(1/4x的平方-xy+y的平方)/(x-2y)=1/4(x-2y)^2/(x-2y)=1/4(x-2y)=x/4-y/2

（x+2y）²×（x-2y）²=[(x+2y)(x-2y)]²=(x²-4y²)²=x⁴-8x²y²+16y

y/(x²-xy)+2/(y-x)-x/(y²-xy)=[y²+2(-xy)+x²]/(x²y-xy²)=(x-y)²/[(x-y

2x(-xy)^2-x^2(x^2y^2-y^2)=(xy)^2(2x-x^2+1)

后面是y分之y的几次方?再问：三次方再答：原式=x^2+xy+x.

原式=(1-x²y²）（x²y²+1）=（1-x四次方y四次方）请指出,希望能和你一起探讨~如果认为我的回答好,请及时采纳,

(x-y)²(x+y)²=[(x-y)(x+y)]²=(x²-y²)²=x的4次方-2x²y²+y的4次方(x-y)&#

原式=x^2/xy-y^2/xy-[(x-y)y]/[(y-x)x]=x/y-y/x+y/x=x/y.

(x的平方-y的平方）的-2次方（x+y)的二次方＝（x+y）^2/(x^2-y^2)=(x+y)^2/(x+y)(x-y)=(x+y)/(x-y)

第2题我来回答吧：由X+2Y=（2X+1）/3X+2Y=（Y-X）/4得：3X+6Y=2X+14X+8Y=Y-X即：X=1-6Y5X+7Y=0消去X,得：23Y=5所以Y=5/23,X=-7/23

【2（x-y）²-8（x-y)²（x+y）+6y（x-y）²】÷2（x-y）²=2（x-y）²÷2(x-y)²-8（x-y)²（x

（-X-y)^2=(-x)^2+2*(-x)*(-y)+(-y)^2=(x)^2+2*x*y+y^2

(-x+2y)^2=(-x)^2+2×（-x)×(2y)+(2y)^2=x^2+4xy+4y^2

(x+3y)^2+(x-3y)^2=2(x^2+9y^2)2(x^2+9y^2)+2(x^4-y^4)=2(x^4+x^2+9y^2-y^4)

感觉是你写错了,应该是下面的这个吧(x+y-z)²-(x-y+z)²=[(x+y-z)-(x-y+z)][(x+y-z)+(x-y+z)]=(x+y-z-x+y-z)(x+y-z+

原式等于：1/[X(X+2Y)].再问：过程再答：原式等于：(x²-4y²)/（x²+4xy+4y²）÷(x²-2xy)=(x²-4y

x-y分之2x的平方-y-x分之x的平方-4xy+x-y分之2y的平方-x的平方=2x/(x-y)-(x²-4xy)/(y-x)+(2y-x²)/(x-y)=(2x+x²